In wireless infrastructure, an RF transmitter TX can include a TX baseband device (ASIC) that transmits TX (digital) data to an analog front end (AFE) device over a serializer-deserializer (SerDes) com link. The AFE converts the serialized TX data, and transmits through a TX RF signal path including upconversion to RF, and transmit through a TX PA (power amplifier). The TX baseband ASIC can be implemented in a transceiver TX/RX that includes a receiver RX baseband device, with a TX/RX AFE and bi-directional TX/RX SerDes com link.
The TX baseband device commonly include DPD (digital pre-distortion) processing of the TX data to compensate for signal path nonlinearities, primarily in the PA. To calibrate/adjust DPD, the TX baseband device commonly includes a feedback channel, such as through a feedback receiver FBRX, for observing the AFE TX output through the TX PA, with the SerDes com link providing TX and RX SerDes data lanes.
TX DPD results in approximately 5× bandwidth expansion, increasing the TX data bandwidth required over the SerDes com link.